In the current context of vigorously promoting the construction of ecological civilization, land consolidation in the construction of the constant pursuit of ecological design, to achieve sustainable use of land resou...In the current context of vigorously promoting the construction of ecological civilization, land consolidation in the construction of the constant pursuit of ecological design, to achieve sustainable use of land resources, China has made great progress in ecological land consolidation. In this paper, through the comparison of flow design and cross section design of agricultural canal design in ecological land remediation and traditional land remediation, the characteristic design of some agricultural canals in ecological land remediation was introduced, and the ecological, social and economic benefits of two land remediation methods were systematically analyzed. The analysis shows that ecological agricultural canals play a great role in protecting biodiversity, alleviating the contradiction between people and land, saving energy, purifying water resources and improving land quality, the research result has provided the basis and the model for the land consolidation in carrying on the ecology type ditch design.展开更多
Pakistan livelihood depends on agriculture and so for this on irrigation system. The irrigation system in Sindh province depends on three barrages. The canals off taking from these three barrages irrigate 5.5 million ...Pakistan livelihood depends on agriculture and so for this on irrigation system. The irrigation system in Sindh province depends on three barrages. The canals off taking from these three barrages irrigate 5.5 million hectares of agriculture land. Sukkur Barrage, which is the oldest one, irrigates more than 2.0 million hectares of land. The Dadu Canal off taking from Sukkur barrage is an earthen canal. A huge amount of irrigation water is lost from the canal in the form of seepage from banks and bed. It is estimated that 40 to 50 per cent of water is lost between the canal head works to the farm-gate. The seepage from the canal creates twin problems of salinity and water logging consequently a large agriculture land has gone out of use, and this process is continued particularly in Sindh. Lining of Canals is considered an effective solution to this problem. But lining of canals in Sindh is a great issue as canals will need to be closed long enough to deprive the farmers at least one crop season and the farmers are unable to pay this price for canal. Therefore, in this study, the Dadu Canal is proposed to be redesigned as an adjacent lined canal which involves design of cross section for various lining options at locations where changes in the hydraulic conditions occur at cross regulators and fall structures. The proposed lining is preferred to be plain cement concrete lining which is selected after investigating local conditions. Quantity and cost estimation at selected RDs (Reduced Distance) proved feasible and significant in long term functioning of Dadu Canal.展开更多
The Grand Canal is the cultural source of Yangzhou's historical development. The heritage and development of the canal culture are conducive to enhancing the image of Yangzhou, building cultural brands, and enhanc...The Grand Canal is the cultural source of Yangzhou's historical development. The heritage and development of the canal culture are conducive to enhancing the image of Yangzhou, building cultural brands, and enhancing core competitiveness. Taking the canal in the Gaomin Temple section of Yangzhou for example, this study was based on the regional canal culture and the humanistic characteristics of Gaomin Temple, and explored the unique cultural communication mode of the important landscape node of the canal. Through the analysis of the status and development of the landscape of the section, this study concluded corresponding cultural orientation content and direction, and analyzed the integration and communication ideas of regional culture in landscape planning and design, in order to provide a reference for the promotion of cultural brands in the canal city of Yangzhou.展开更多
This paper addresses a comprehensive design of RCC T-beam Bridge based on AASHTO design standards. The bridge is designed and proposed to be constructed over an irrigation canal (Zahirshahi canal) of Kandahar province...This paper addresses a comprehensive design of RCC T-beam Bridge based on AASHTO design standards. The bridge is designed and proposed to be constructed over an irrigation canal (Zahirshahi canal) of Kandahar province, Afghanistan that has more than 30 bridges over it. Yet they are not enough, and the demand for construction of new bridges is gradually arising because of the vast urbanization in the surrounding of the canal. Most of the bridges on this canal are Reinforced Concrete Slab (RCS) bridges;?these type bridges are limited by capacity and are generally found only in smaller spans. Since they can only span short distances and are often constructed as multiple-span?bridges with vertical supports between the abutments to allow a longer length.?All constructed slab bridges over Zahirshahi canal are four-span bridges. Constructing multi-span bridges on the canal decreases waterway due to the existence of many piers and footings that could increase the water level during the peak flow, even, sometimes can cause over flow. Taking into consideration these deficiencies of the present (RCS) bridges, two-span RCC T-beam Bridge is one of the best alternatives to be constructed over the canal. In addition, canal cross-sectional dimensions are almost constant along its length, though the construction of two-span RCC T-beam bridge is applicable at any point of the canal. The design is selected based on exclusive survey of the area during all seasons including the peak flowing of the canal.展开更多
In designing a canal system, a major problem is to decide what conveyance parameter to apply in the calculations. Since basic knowledge on this subject is lacking, it is usually taken from literatures. Most of the irr...In designing a canal system, a major problem is to decide what conveyance parameter to apply in the calculations. Since basic knowledge on this subject is lacking, it is usually taken from literatures. Most of the irrigation projects in Ethiopia are found to work below their expectation. One of the main reasons is the conveyance parameters variation from the expected (design) value which ultimately affects the envisioned conveyance efficiency. To evaluate this variation, Fentale irrigation scheme was used as case study. The conveyance efficiency used at the design stage was 80%, which was within Food and Agricultural Organization of the united nations recommendations;while the field survey value was 17%. Such huge variation was due to the fact that the assigned conveyance parameter values (roughness coefficient, hydraulic radius and bed slope) no longer represent the current situation of the scheme. Such variation has resulted in increase in the depth and top width of the water surface which further resulted in 13% and 3% increase in wetted perimeter and top width of the canal, respectively. Thus this study suggests that conveyance parameters shall be derived from history of existing irrigation schemes in a country, rather than adopting it from standard literatures. As such construction quality, maintenance activities and technological transfer activities in a country shall be seen in deciding the conveyance parameters. The study also suggests that the ever increasing water shortage in an irrigation project could be managed by proper maintenance of the entire irrigation system.展开更多
文摘In the current context of vigorously promoting the construction of ecological civilization, land consolidation in the construction of the constant pursuit of ecological design, to achieve sustainable use of land resources, China has made great progress in ecological land consolidation. In this paper, through the comparison of flow design and cross section design of agricultural canal design in ecological land remediation and traditional land remediation, the characteristic design of some agricultural canals in ecological land remediation was introduced, and the ecological, social and economic benefits of two land remediation methods were systematically analyzed. The analysis shows that ecological agricultural canals play a great role in protecting biodiversity, alleviating the contradiction between people and land, saving energy, purifying water resources and improving land quality, the research result has provided the basis and the model for the land consolidation in carrying on the ecology type ditch design.
文摘Pakistan livelihood depends on agriculture and so for this on irrigation system. The irrigation system in Sindh province depends on three barrages. The canals off taking from these three barrages irrigate 5.5 million hectares of agriculture land. Sukkur Barrage, which is the oldest one, irrigates more than 2.0 million hectares of land. The Dadu Canal off taking from Sukkur barrage is an earthen canal. A huge amount of irrigation water is lost from the canal in the form of seepage from banks and bed. It is estimated that 40 to 50 per cent of water is lost between the canal head works to the farm-gate. The seepage from the canal creates twin problems of salinity and water logging consequently a large agriculture land has gone out of use, and this process is continued particularly in Sindh. Lining of Canals is considered an effective solution to this problem. But lining of canals in Sindh is a great issue as canals will need to be closed long enough to deprive the farmers at least one crop season and the farmers are unable to pay this price for canal. Therefore, in this study, the Dadu Canal is proposed to be redesigned as an adjacent lined canal which involves design of cross section for various lining options at locations where changes in the hydraulic conditions occur at cross regulators and fall structures. The proposed lining is preferred to be plain cement concrete lining which is selected after investigating local conditions. Quantity and cost estimation at selected RDs (Reduced Distance) proved feasible and significant in long term functioning of Dadu Canal.
基金Sponsored by 2018 Philosophy and Social Science Research Funded Project in Colleges and Universities of Jiangsu Provincial Department of Education(2018SJA1193)
文摘The Grand Canal is the cultural source of Yangzhou's historical development. The heritage and development of the canal culture are conducive to enhancing the image of Yangzhou, building cultural brands, and enhancing core competitiveness. Taking the canal in the Gaomin Temple section of Yangzhou for example, this study was based on the regional canal culture and the humanistic characteristics of Gaomin Temple, and explored the unique cultural communication mode of the important landscape node of the canal. Through the analysis of the status and development of the landscape of the section, this study concluded corresponding cultural orientation content and direction, and analyzed the integration and communication ideas of regional culture in landscape planning and design, in order to provide a reference for the promotion of cultural brands in the canal city of Yangzhou.
文摘This paper addresses a comprehensive design of RCC T-beam Bridge based on AASHTO design standards. The bridge is designed and proposed to be constructed over an irrigation canal (Zahirshahi canal) of Kandahar province, Afghanistan that has more than 30 bridges over it. Yet they are not enough, and the demand for construction of new bridges is gradually arising because of the vast urbanization in the surrounding of the canal. Most of the bridges on this canal are Reinforced Concrete Slab (RCS) bridges;?these type bridges are limited by capacity and are generally found only in smaller spans. Since they can only span short distances and are often constructed as multiple-span?bridges with vertical supports between the abutments to allow a longer length.?All constructed slab bridges over Zahirshahi canal are four-span bridges. Constructing multi-span bridges on the canal decreases waterway due to the existence of many piers and footings that could increase the water level during the peak flow, even, sometimes can cause over flow. Taking into consideration these deficiencies of the present (RCS) bridges, two-span RCC T-beam Bridge is one of the best alternatives to be constructed over the canal. In addition, canal cross-sectional dimensions are almost constant along its length, though the construction of two-span RCC T-beam bridge is applicable at any point of the canal. The design is selected based on exclusive survey of the area during all seasons including the peak flowing of the canal.
文摘In designing a canal system, a major problem is to decide what conveyance parameter to apply in the calculations. Since basic knowledge on this subject is lacking, it is usually taken from literatures. Most of the irrigation projects in Ethiopia are found to work below their expectation. One of the main reasons is the conveyance parameters variation from the expected (design) value which ultimately affects the envisioned conveyance efficiency. To evaluate this variation, Fentale irrigation scheme was used as case study. The conveyance efficiency used at the design stage was 80%, which was within Food and Agricultural Organization of the united nations recommendations;while the field survey value was 17%. Such huge variation was due to the fact that the assigned conveyance parameter values (roughness coefficient, hydraulic radius and bed slope) no longer represent the current situation of the scheme. Such variation has resulted in increase in the depth and top width of the water surface which further resulted in 13% and 3% increase in wetted perimeter and top width of the canal, respectively. Thus this study suggests that conveyance parameters shall be derived from history of existing irrigation schemes in a country, rather than adopting it from standard literatures. As such construction quality, maintenance activities and technological transfer activities in a country shall be seen in deciding the conveyance parameters. The study also suggests that the ever increasing water shortage in an irrigation project could be managed by proper maintenance of the entire irrigation system.
